1. Field of the Invention
This invention relates to skylight structures in general and more particularly to the combination of a skylight structure having a light intensity reducing mechanism for selectively admitting high and lower intensity light.
2. Description of the Prior Art
As is well known, a skylight is a structure formed in the roof of a building for admitting natural light into the building, and such structures have been used for many years. Although skylights differ somewhat in size and configuration, they all have a light admitting window that is carried in a suitable frame which is mounted on the roof of a building in a position above an opening provided in the roof. In modern skylights, the light admitting windows are usually formed of plastic and are molded in a dome shape, and some of them are hingedly mounted for opening to provide ventilation capabilities. Skylights further include a light shaft structure which extends downwardly from the opening in the roof through the attic of the building and opens up onto the ceiling of the room below the skylight. Some skylights have a translucent light difuser panel mounted in the ceiling at the bottom end of the light shaft and some are left open.
On a bright sunshiny day, the light admitted to a room through a skylight can be excessively intense and some prior art attempts have been made to provide solutions to the light intensity problem.
U.S. Pat. No. 1,888,522 discloses a plurality of juxtaposed opaque slats which are carried in a frame and are interconnected for ganged adjustment much in the manner of a venetian blind and a pull cord arrangement is provided for blind adjustment purposes. This venetian blind type of structure is mounted in the light shaft enclosing structure proximate the lower open end thereof and the pull cord hangs down through the open end into the room. As is the case with venetian blinds, and the special structure disclosed in this prior art patent, this type of blind will freely pass light when open, completely block the passage of light when fully closed, and can be adjusted to an intermediate position between fully opened and fully closed. When in such an intermediate position, some light will be blocked and some will freely pass through the openings between the juxtaposed opaque slats, and this passed light will be at full intensity. In addition to the lack of a light intensity reducing capability, i.e., dimming, the special blind structure disclosed in this patent is relatively complex and thus costly.
Another skylight blind structure of this same general type is commercially available. This blind is a pleated opaque shade which may be contracted and extended in the manner of a bellows or an accordion. The shade is formed of fabric which is bonded to aluminum and is carried for slidable movement in a frame that is mounted in the light shaft of the skylight. Due to the opaque nature of this accordion pleated blind, it lacks the capability of reducing light intensity of the admitted light when in an intermediate position and is relatively complex and thus costly as in the above described prior art patent. An extension rod having a special blind engaging end is needed to accomplish the sliding adjustment movements of this blind structure and the rod is used by placing it into the open bottom end of the light shaft into demountable engagement with the blind.
Both of the above described blind structures must be used in skylights of the type which are open on the bottom end of their light shafts. The pull cord arrangement hanging down from the above described venetian blind type of structure, and the need to provide open access for the extension rod used with the accordion pleated blind, precludes the use of these blinds in skylight structures having the ceiling mounted translucent light difuser panels, which is used in a great number of skylights.
To the best of my knowledge, no device has been provided or suggested which may be used in virtually any skylight and is capable of reducing the intensity of the light entering into a room through a skylight.